1. Field of the Invention
This invention relates to operating assemblies or operators for jalousie windows, and more particularly, to a lever-based operator and a secondary locking mechanism.
2. Prior Art
Jalousie windows generally include louvers extending across and pivoted in a rectangular window frame. The louvers are often rectangular and are generally mounted in the window frame at vertically spaced locations, often in such a way that, when the louvers are fully closed, opposing horizontal edges of adjacent louvers either abut each other or preferably overlap slightly such that upper louvers lap over lower louvers on the outside of the window. The louvers are parallel and substantially horizontal when fully open, thereby opening vertical spaces between the horizontal louvers for airflow, line-of-sight, etc.
The louvers are mounted on parallel horizontal pivot axes and are mechanically linked to open or close as a unit. To open the louvers, a user actuates an operating mechanism to rotate the louvers outwardly around a horizontal axis at or near the upper horizontal edges of each louver. In this way, the jalousie window provides light and ventilation by allowing air to pass between the opened louvers.
One mechanism for operating a jalousie window generally includes a rotatable crank with associated pinions and gears. Rotation of the crank is transformed into translational displacement of a window bar operatively connected to the louvers, that is, translational displacement of the window bar causes the louvers to open or shut. The window bar can be an integral connecting bar pivotally attached at regular intervals to the louvers, in each case at a space from their pivot axes. Alternatively, a connecting linkage having plural links coupling adjacent louvers to the operating mechanism can operate all the louvers as a unit.
Jalousie windows are applied in a variety of settings having different needs for ventilation, light transmission, appearance, security and the like. Applications range from heavy industrial to residential, and may concern windows or doors of buildings, porches and sunrooms, mobile homes and other vehicles. The louvers often comprise glass, plexiglass or other transparent or translucent material, and in the commercial context may comprise metal or another opaque material. Jalousie structures also serve as vents for manufacturing plants and other industrial facilities and structures as well as fire-damping controllable closures in HVAC ducts, which also may be considered windows in accordance with the invention. Metal-louver jalousie windows are also useful when security is an issue.
New building codes require that windows resist "wind-load" in both positive and negative conditions (inward and outward). The structure of jalousie windows inherently provides significant locking of the louvers against positive (inward) pressure, since the louvers rest directly against one another when closed. Positive loads tend to cause the louvers to close tighter. However, against negative (outward) pressure, the structure is inherently weak. When negative (outward) pressure is applied, prior art louvers often tend to open outwardly, resisted if at all only by the frictional resistance of the operating mechanism. It is not desirable that the operating mechanism have substantial frictional resistance. Therefore, the opening of the louvers may be a significant problem, especially during heavy storm conditions or when a mechanical force is applied by a burglar or the like.
The material, size and thickness of the louvers are selected to suit the security and other demands of the particular application. The number of louvers and their respective dimensions vary depending on the size of the jalousie window, as well as the particular industrial, commercial, or residential application. A jalousie window of a given size may have relatively more louvers that are narrow or fewer louvers that are wide. Wide louvers pivoted at their top edges can present a substantial weight when open, producing a force resisted by the friction of the operating mechanism. For wide louvers, the pivot axes can be spaced downwardly from the top edges to more nearly balance the louvers and thereby reduce the applied force. However, this is less desirable than placing the pivot near the top edge so that the louvers open outwardly.
It is desirable for jalousie windows--of whatever configuration--to be straightforward and relatively easy for the user to operate, while at the same time satisfying ventilation, security, access, and other requirements associated with windows. Jalousie windows typically are opened and closed by winding a crank mechanism comprising worm and pinion gears arranged to translate the window bar coupled to the louvers. The mechanical advantage of the gearing enables the user to turn the crank readily to open, close or otherwise adjust the jalousie window to maintain a desired louver angle. As a trade-off for mechanical advantage, multiple turns of the crank may be needed to move the louvers between the fully closed and fully open positions.
The louvers should remain at the desired angle where they are set, not tend to sag toward the closed position due to gravity or to open further under wind pressure. A worm and pinion mechanism or the like, having a substantial or moderate gear reduction ratio, can provide the necessary frictional resistance to hold the louvers in place. However, friction makes the mechanism more difficult to operate, and may dictate a need for even greater mechanical advantage.
Some of the same considerations apply to jalousie structures used, for example, as automatically operable ventilation dampers. Ventilation dampers are normally maintained in either the fully opened or fully closed position, unlike windows wherein the louvers are adjusted to remain at any desired angle. Nevertheless, a certain force and stroke length is needed to translate the connecting bar and the louvers between the fully open and closed positions. Mechanical advantage, stroke length and power constraints affect the nature of the operating mechanism and the source of motive power (for example, a gear motor, solenoid, etc.) as well as its cost.
In more general terms, the need to make a jalousie structure relatively easy to operate acts as a design constraint potentially limiting not only the size, shape, and number of louvers, but also dictating the configuration, gearing ratios, relative sizes, and other aspects of the other moving components of the window. These constraints are especially important for large or heavy jalousie windows such as security windows having cantilevered louvers made out of heavy material such as steel, or whenever security or other design requirements necessitate a robust construction with heavy louvers and sturdy moving parts. In other words, if the louvers and moving components of a given jalousie window design need to be relatively heavy, it can be difficult to design a correspondingly robust operating mechanism which meets the user's need to operate the window without excessive exertion, to cause the louvers to maintain a desired louver angle, and to do so at reasonable cost.
Accordingly, there is a need for a durable jalousie window and operating mechanism that is easy to operate, delivers sufficient actuating force for a wide variety of jalousie window designs, and maintains a selected louver angle without introducing excessive frictional resistance. Additionally, without contributing to frictional resistance, there is a need for a design that permits a jalousie window to be fixed, especially in its fully closed position, to avoid unwanted opening of the window during negative (outward) air pressure conditions or vibration and flapping of the louvers during gusts. There is a further need for such operating mechanism and secondary lock to be relatively straightforward and inexpensive to manufacture.